diff --git a/src/ca/addrList.h b/src/ca/addrList.h
index 6d0e4a71b..69eb47098 100644
--- a/src/ca/addrList.h
+++ b/src/ca/addrList.h
@@ -7,15 +7,16 @@ extern "C" {
 #endif
 
 epicsShareFunc void epicsShareAPI configureChannelAccessAddressList 
-        (ELLLIST *pList, SOCKET sock, unsigned short port);
+    ( ELLLIST *pList, SOCKET sock, unsigned short port );
 
 epicsShareFunc void epicsShareAPI addAddrToChannelAccessAddressList 
-    (ELLLIST *pList, const ENV_PARAM *pEnv, unsigned short port);
+    ( ELLLIST *pList, const ENV_PARAM *pEnv, unsigned short port );
 
-epicsShareFunc void epicsShareAPI printChannelAccessAddressList (const ELLLIST *pList);
+epicsShareFunc void epicsShareAPI printChannelAccessAddressList 
+    ( const ELLLIST *pList );
 
-epicsShareFunc void epicsShareAPI setPortAndRemoveDuplicates 
-    (ELLLIST *pDestList, ELLLIST *pSrcList, unsigned short port);
+epicsShareFunc void epicsShareAPI removeDuplicatesAddresses
+    ( ELLLIST *pDestList, ELLLIST *pSrcList );
 
 #ifdef __cplusplus
 }
diff --git a/src/ca/iocinf.cpp b/src/ca/iocinf.cpp
index b1179bd01..8d582b4ff 100644
--- a/src/ca/iocinf.cpp
+++ b/src/ca/iocinf.cpp
@@ -78,6 +78,7 @@ epicsShareFunc void epicsShareAPI addAddrToChannelAccessAddressList
         }
 
         pNewNode->addr.ia = addr;
+        memset ( &pNewNode->netMask, '\0', sizeof ( pNewNode->netMask ) );
 
 		/*
 		 * LOCK applied externally
@@ -89,30 +90,26 @@ epicsShareFunc void epicsShareAPI addAddrToChannelAccessAddressList
 }
 
 /*
- * setPortAndRemoveDuplicates ()
+ * removeDuplicatesAddresses ()
  */
-epicsShareFunc void epicsShareAPI setPortAndRemoveDuplicates 
-    (ELLLIST *pDestList, ELLLIST *pSrcList, unsigned short port)
+epicsShareFunc void epicsShareAPI removeDuplicatesAddresses 
+    ( ELLLIST *pDestList, ELLLIST *pSrcList )
 {
     osiSockAddrNode *pNode;
 
-    /*
-     * eliminate duplicates and set the port
-     */
     while ( (pNode  = (osiSockAddrNode *) ellGet ( pSrcList ) ) ) {
         osiSockAddrNode *pTmpNode;
 
         if ( pNode->addr.sa.sa_family == AF_INET ) {
-            /*
-             * set the correct destination port
-             */
-            pNode->addr.ia.sin_port = htons (port);
 
             pTmpNode = (osiSockAddrNode *) ellFirst (pDestList);
             while ( pTmpNode ) {
                 if (pTmpNode->addr.sa.sa_family == AF_INET) {
-                    if (pNode->addr.ia.sin_addr.s_addr == pTmpNode->addr.ia.sin_addr.s_addr && 
-                        pNode->addr.ia.sin_port == pTmpNode->addr.ia.sin_port) {
+                    unsigned netMask = pNode->netMask.ia.sin_addr.s_addr | 
+                        pTmpNode->netMask.ia.sin_addr.s_addr;
+                    unsigned exorAddr = pNode->addr.ia.sin_addr.s_addr ^ pTmpNode->addr.ia.sin_addr.s_addr;
+                    exorAddr &= netMask;
+                    if ( exorAddr == 0u && pNode->addr.ia.sin_port == pTmpNode->addr.ia.sin_port) {
                         char buf[64];
                         ipAddrToDottedIP ( &pNode->addr.ia, buf, sizeof (buf) );
                         ca_printf ( "Warning: Duplicate EPICS CA Address list entry \"%s\" discarded\n", buf );
@@ -133,6 +130,23 @@ epicsShareFunc void epicsShareAPI setPortAndRemoveDuplicates
     }
 }
 
+/*
+ * forcePort ()
+ */
+static void  forcePort (ELLLIST *pList, unsigned short port)
+{
+    osiSockAddrNode *pNode;
+
+    pNode  = (osiSockAddrNode *) ellFirst ( pList );
+    while ( pNode ) {
+        if ( pNode->addr.sa.sa_family == AF_INET ) {
+            pNode->addr.ia.sin_port = htons (port);
+        }
+        pNode = (osiSockAddrNode *) ellNext ( &pNode->node );
+    }
+}
+
+
 /*
  * configureChannelAccessAddressList ()
  */
@@ -183,17 +197,21 @@ epicsShareFunc void epicsShareAPI configureChannelAccessAddressList
                  */
                 pNewNode->addr.ia.sin_family = AF_INET;
                 pNewNode->addr.ia.sin_addr.s_addr = htonl ( INADDR_LOOPBACK );
+                pNewNode->addr.ia.sin_port = htons ( port );
+                memset ( &pNewNode->netMask, '\0', sizeof ( pNewNode->netMask ) );
                 ellAdd ( &tmpList, &pNewNode->node );
             }
             else {
                 errlogPrintf ( "configureChannelAccessAddressList(): no memory available for configuration\n" );
             }
         }
+        else {
+            forcePort ( &tmpList, port );
+        }
     }
-
     addAddrToChannelAccessAddressList ( &tmpList, &EPICS_CA_ADDR_LIST, port );
 
-    setPortAndRemoveDuplicates (pList, &tmpList, port);
+    removeDuplicatesAddresses ( pList, &tmpList );
 }
 
 
diff --git a/src/cas/io/bsdSocket/casDGIntfIO.cc b/src/cas/io/bsdSocket/casDGIntfIO.cc
index f3a4c7004..1320ba261 100644
--- a/src/cas/io/bsdSocket/casDGIntfIO.cc
+++ b/src/cas/io/bsdSocket/casDGIntfIO.cc
@@ -37,6 +37,24 @@
 #include "server.h"
 #include "addrList.h"
 
+
+/*
+ * forcePort ()
+ */
+static void  forcePort (ELLLIST *pList, unsigned short port)
+{
+    osiSockAddrNode *pNode;
+
+    pNode  = (osiSockAddrNode *) ellFirst ( pList );
+    while ( pNode ) {
+        if ( pNode->addr.sa.sa_family == AF_INET ) {
+            pNode->addr.ia.sin_port = htons (port);
+        }
+        pNode = (osiSockAddrNode *) ellNext ( &pNode->node );
+    }
+}
+
+
 //
 // casDGIntfIO::casDGIntfIO()
 //
@@ -44,12 +62,14 @@ casDGIntfIO::casDGIntfIO (caServerI &serverIn, const caNetAddr &addr,
                           bool autoBeaconAddr, bool addConfigBeaconAddr) :
     casDGClient (serverIn)
 {
+    ELLLIST BCastAddrList;
     osiSockAddr serverAddr;
     osiSockAddr serverBCastAddr;
     int status;
     unsigned short beaconPort;
     
-    ellInit(&this->beaconAddrList);
+    ellInit ( &BCastAddrList );
+    ellInit ( &this->beaconAddrList );
     
     if ( ! osiSockAttach () ) {
         throw S_cas_internal;
@@ -90,10 +110,8 @@ casDGIntfIO::casDGIntfIO (caServerI &serverIn, const caNetAddr &addr,
     // discover beacon addresses associated with this interface
     //
     {
-        ELLLIST BCastAddrList;
         osiSockAddrNode *pAddr;
 
-        ellInit (&BCastAddrList);
         osiSockDiscoverBroadcastAddresses (&BCastAddrList, 
             this->sock, &serverAddr); // match addr 
         if (ellCount(&BCastAddrList)<1) {
@@ -106,7 +124,7 @@ casDGIntfIO::casDGIntfIO (caServerI &serverIn, const caNetAddr &addr,
         serverBCastAddr.ia.sin_port = htons (this->dgPort);
 
         if (autoBeaconAddr) {
-            setPortAndRemoveDuplicates (&this->beaconAddrList, &BCastAddrList, beaconPort);
+            forcePort (&BCastAddrList,beaconPort);
         }
         else {
             ellFree (&BCastAddrList);
@@ -144,9 +162,11 @@ casDGIntfIO::casDGIntfIO (caServerI &serverIn, const caNetAddr &addr,
         // add in the configured addresses
         //
         addAddrToChannelAccessAddressList (
-            &this->beaconAddrList, pParam, beaconPort);
+            &BCastAddrList, pParam, beaconPort);
     }
-       
+ 
+    removeDuplicatesAddresses ( &this->beaconAddrList, &BCastAddrList );
+
 	//
     // Solaris specific:
 	// If they are binding to a particular interface then